Mixed mode transceiver system

ABSTRACT

A radiotelephone system comprised of a radiotelephone-pair suitably intercoupled theretogether to permit transfer of data, such as NAM information, therebetween. A first of the radiotelephone-pair comprises a radiotelephone of conventional construction. A second radiotelephone of the radiotelephone-pair comprises a radiotelephone having circuitry to transmit efficiently an information signal upon a cellular, communication system of increased capacity. The data sequence contained in the first radiotelephone is transferred to the second radiotelephone to permit a communication link to be formed between the second radiotelephone and a cellular, communication network.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of application Ser. No. 08/383,588, filed Feb. 2,1995 and now abandoned, which is a continuation of application Ser. No.08/112,031, filed Aug. 26, 1993 and now abandoned, which is acontinuation of application Ser. No. 07/653,835 filed on Feb. 11, 1991which was a continuation-in-part of application Ser. No. 107,227, filedOct. 9, 1987, and now U.S. Pat. No. 5,029,233, issued Jul. 2, 1991.

BACKGROUND OF THE INVENTION

The present invention relates generally to wireless communicationsystems, and, more particularly, to a mixed-mode transceiver system fora radiotelephone-pair which permits generation of a communication linkwith a fixed station of the communication system by the transmission ofa code contained in either one of the radiotelephones comprising theradiotelephone-pair.

A communication system which transmits information between two locationsincludes, at a minimum, a transmitter and a receiver interconnected by atransmission channel. Communication between the transmitter and thereceiver is effectuated by transmission of the information, in the formof an information signal, upon the transmission channel.

In one type of communication system, a radio communication system, thetransmission channel is comprised of a radio-frequency channel whichinterconnects the transmitter and the receiver. To transmit aninformation signal (sometimes referred to as a baseband signal) upon theradio-frequency channel, the information signal must be converted into aform suitable for transmission thereof upon the radio-frequency channel.

Conversion of the information signal (i.e., the baseband signal) into asignal suitable for transmission upon the radio-frequency channel isaccomplished by a process referred to as modulation wherein theinformation signal is impressed upon a radio-frequency electromagneticwave. The radio-frequency electromagnetic wave is of a frequency of avalue within a range of values of frequencies which defines theradio-frequency channel. The radio-frequency electromagnetic wave iscommonly referred to as a carrier signal, and the radio-frequencyelectromagnetic wave, once modulated by the information signal, isreferred to as a modulated, information signal.

The information content of the resultant, modulated, information signaloccupies a range of frequencies, centered at, or close to, the frequencyof the carrier signal. Because the modulated, information signal may betransmitted through free-space upon the radio-frequency channel totransmit thereby the information content of the information signalbetween the transmitter and the receiver of the communication system,the transmitter and the receiver need not be positioned in closeproximity with one another.

Various modulation techniques have been developed to modulate theinformation signal upon the carrier signal to transmit thereby theinformation signal upon the radio-frequency transmission channel. Suchmodulation techniques include, but not by way of limitation: amplitudemodulation (AM), frequency modulation (FM), and phase modulation (PM).

The receiver of the communication system which receives the modulated,information signal transmitted upon the transmission channel containscircuitry to detect, or to recreate otherwise, the information signal.Typically, the circuitry of the receiver includes circuitry (sometimesconsisting of several stages) to convert downward in frequency thereceived, modulated, information signal. The process of detecting, orrecreating, the information signal is referred to as demodulation, andsuch circuitry for performing demodulation is referred to asdemodulation circuitry.

A plurality of modulated, information signals may be simultaneouslytransmitted as long as the simultaneously-transmitted, modulated,information signals are comprised of carrier signals of dissimilarfrequencies, and the resultant, modulated, information signals do notoverlap in frequency.

A receiver includes tuning and other filter circuitry to pass onlycertain of the signals received by the receiver. Such tuning and otherfilter circuitry form frequency passbands for passing signals, orcomponent portions of signals, having frequencies within the passbandsof such circuitry.

The broad range of frequencies of which the carrier signal may becomprised, and upon which the information signal may be modulated, isreferred to as the electromagnetic frequency spectrum. Regulatory bodieshave divided the electromagnetic frequency spectrum into frequencybands; the frequency bands may be further divided into frequencychannels, such channels may, for example, form the transmissionchannels, as above-described, of a communication system. Regulation ofthe transmission of radio-frequency signals in certain of the frequencybands of the electromagnetic frequency spectrum minimize interferencebetween simultaneously-transmitted, modulated, information signals.

Portions of a 100 MHz frequency band extending between 800 MHz and 900MHz are allocated in the United States for radiotelephone communication.Radiotelephone communication, may, for example, be effectuated by aradiotelephone (or other transceiver) utilized in a cellular,communication system. A radiotelephone is operative both to transmit andto receive radio-frequency, modulated, information signals. Two-waycommunication is permitted between the radiotelephone and aremotely-located transceiver.

In general, a cellular, communication system is comprised of a fixedcommunication network which transmits modulated, information signals to,and receives modulated, information signals from, radiotelephones. Thefixed, communication network is created by positioning numerous basestations at spaced-apart locations throughout a geographical area. Abase station forms a fixed site which contains circuitry to receivemodulated, information signals transmitted by one, or many,radiotelephones, and to transmit modulated, information signals to theone, or many, radiotelephones. Because both the fixed site formed of thebase station and a radiotelephone permits both transmission andreception of modulated, information signals, two-way communicationbetween a radiotelephone and a base station is permitted. The basestations are connected to a conventional, wireline telephone systemthrough switching centers.

The position at which each of the base stations of the cellular,communication system is located is carefully selected so that at leastone base station is within the reception range of a radiotelephonepositioned at any location throughout the geographical area. Because ofthe spaced apart nature of the positioning of the base stations,portions of the geographical area throughout which the base stations arelocated are associated with individual ones of the base stations.Portions of the geographical area positioned proximate to each of thespaced-apart base stations define "cells" wherein a plurality of cells,each associated with a base station, together form the geographical areaencompassed by the cellular, communication system. A radiotelephonepositioned within the boundaries of any of the cells of the cellular,communication system may transmit, and receive, modulated, informationsignals to, and from, at least one base station.

Radiotelephones utilized in such a cellular, communication system are ofmany varied constructions. One construction of radiotelephone, referredto generically as a mobile radiotelephone, is affixed in position in avehicle, such as an automobile. Affixation of the mobile radiotelephonein the vehicle is advantageous for the reason that the power requiredfor operation of the mobile radiotelephone may be supplied by thevehicular power supply. Therefore, the mobile radiotelephone may beoperated at relatively high power levels to increase the transmissionrange, and reception range, of modulated, information signalstransmitted by the mobile radiotelephone. However, because the mobileradiotelephone is affixed in position within the vehicle, portability ofthe mobile radiotelephone is minimal in some constructions, and in otherconstructions, although permitting of removal from the vehicle, theportability of the radiotelephone is limited due to the generally largephysical size of the mobile radiotelephone. Further, because the mobileradiotelephone is powered by the vehicular power supply when affixed tothe vehicle, subsequent to removal of the mobile radiotelephone from thevehicle, an alternate source of power is required to permit operation ofthe mobile radiotelephone.

Portable radiotelephones are of constructions to permit convenientcarriage by a user. To permit such portability, a portable power supply(e.g., a battery pack) is affixed to the portable radiotelephone topower the portable radiotelephone thereby. Because the portable powersupply stores only a finite amount of energy, the time period duringwhich the portable radiotelephone may be powered is limited. Once thestored energy of a portable power supply is depleted beneath a minimumlevel, the supply must be replaced with another portable power supply topermit continued operation of the portable radiotelephone.

To increase the length of time during which the portable radiotelephonemay be powered by a single portable power supply, attempts are made tominimize the power level at which the portable radiotelephone isoperated, and generally, the maximum power level at which the portableradiotelephone may be operated is less than the maximum power level atwhich the mobile radiotelephone may be operated. The maximumtransmission and reception range of a portable radiotelephone is,therefore, generally less than the maximum transmission and receptionrange of a mobile radiotelephone.

It may be discerned that radiotelephones are constructed to optimizecertain design parameters. Optimization of certain of the designparameters prevents optimization of other of the design parameters. Forinstance, a portable radiotelephone design optimizes the physicaldimensions thereof to increase thereby the portability of the device.The maximum output power of such a portable radiotelephone cannot beoptimized, as the size of the power supply would be too large.Conversely, a mobile radiotelephone may be constructed to maximizeoperational power output levels as a mobile radiotelephone generallyneed not optimize size parameters.

In the past, therefore, careful consideration of the intended use of theradiotelephone was required to ensure that the radiotelephone was of aconstruction which optimized desired ones of the design parameters.

The need of a user alternately to utilize a mobile radiotelephone inwhich certain ones of the design parameters are optimized, and aportable radiotelephone in which other ones of the design parameters areoptimized in some instances requires the user to purchase both a mobileradiotelephone and a portable radiotelephone. In the past, when a userrequired both a mobile radiotelephone and a portable radiotelephone,payment of an access fee was required to provide each of theradiotelephones with distinct access codes to permit each of theradiotelephones to access the communication network (i.e., the fixedsites comprised of the spaced-apart base stations) of the cellular,communication system. Even when simultaneous use of the two telephoneswas not anticipated or desired, the user was required to obtain suchaccess codes for each radiotelephone.

Disclosed in U.S. Pat. No. 5,029,233, by Michael P. Metroka, co-inventorof the present invention, is a radio arrangement in which two separateradiotelephones are intercoupled such that an access code, required toform the communication link with the communication network, contained inone of the radiotelephones may be transferred to the other of theradiotelephones to permit the other of the radiotelephones to form acommunication link with the communication network. Such an arrangementis advantageous as a user is required to obtain only one access code,and, hence, pay only one access fee, but is still able to utilize bothof the radiotelephones.

As an example, a user having both a mobile radiotelephone and a portableradiotelephone may pay an access fee to provide the portableradiotelephone with an access code to permit thereby the portableradiotelephone to form a communication link with the communicationnetwork. By intercoupling the portable radiotelephone containing theaccess code with the mobile radiotelephone, the access code contained inthe portable radiotelephone may be transferred to the mobileradiotelephone. The access code transferred to the mobile radiotelephonemay be utilized by the mobile radiotelephone to form a communicationlink with the communication network. One such radiotelephone arrangementis the 9800XL extended system sold by Motorola, Inc. The access codecontained in one of the radiotelephones is conventionally contained (butnot by of necessity) in the portable radiotelephone as, once the userexits the vehicle in which the mobile radiotelephone is affixed, theportable radiotelephone may be carried by the user and then thereafterbe utilized to form a communication link with the communication networkto communicate therethrough.

Increased usage of cellular, communication systems has resulted, in manyinstances, in the full utilization of every available transmissionchannel of the frequency band allocated for cellular, radiotelephonecommunication. As a result, various ideas have been proposed to utilizemore efficiently the frequency band allocated for radiotelephonecommunications. More efficient utilization of the frequency bandallocated for radiotelephone communication increases the transmissioncapacity of a cellular, communication system.

One such manner by which the transmission capacity of the cellular,communication system may be increased is to utilize a digital, or otherdiscrete, modulation technique. When an information signal is convertedinto discrete form, a single transmission channel may be utilized totransmit, sequentially, more than one signal. Because more than oneinformation signal may be transmitted upon a single transmissionchannel, the transmission capacity of an existing frequency band may beincreased by a multiple of two or more.

Another such manner by which the transmission capacity of the cellular,communication system may be increased is to reduce the bandwidth of eachtransmission channel upon which the modulated, information signal istransmitted. Such a reduction in the bandwidth allocated for eachtransmission channel, of course, requires the bandwidth of themodulated, information signal to be commensurately reduced. For example,by reducing the bandwidth of each of the transmission channels of theallocated frequency band by a factor of two, the transmission capacityof an existing frequency band may be increased by a multiple of two.Reduction in the bandwidth of the transmission channels by othermultiples, of course, results in a similar, corresponding increase intransmission capacity.

Adoption of any of the above-mentioned ideas for increasing transmissioncapacity of an existing, cellular system would require use of aradiotelephone construction capable of generating modulated, informationsignals which may be transmitted upon such a system of increasedcapacity. For instance, utilization of a digital, or other discrete,modulation technique would require a radiotelephone capable of forming adiscretely-encoded, modulated, information signal. Similarly,utilization of a reduced-bandwidth, modulation technique would require aradiotelephone capable of forming a modulated, information signal of thereduced bandwidth.

The great majority of existing radiotelephones are of constructionswhich permit transmission of modulated, information signals uponexisting cellular, communication systems. Such existing radiotelephonesdo not generate modulated, information signals capable of generating thesignals, as above-described, required to utilize advantageouslyproposed, cellular communication systems of increased capacity.Therefore, to obtain benefit of the increased capacity of proposed,cellular, communication systems, purchase of radiotelephones of newdesign would be required.

To permit continued use of existing radiotelephone constructions,systems proposed to implement any of the above-mentioned ideas permitboth use of radiotelephone constructions of existing design as well asradiotelephone constructions of designs permitting advantageousutilization of the systems of increased capacity. Radiotelephoneconstructions of existing design are still, and would remain, quitefunctional and operable in such systems of increased capacity.Additionally, in many instances, the transmission channels of thefrequency band allocated for cellular, radiotelephone communication arefully utilized during only certain periods of the day (for example,during morning and evening rush hour time periods). Further, onlycertain, cellular systems, generally those located at, or close to,certain urban centers, have reached such full utilization of theexisting frequency band. In short, even with the introduction of suchsystems of increased capacity, radiotelephone constructions of existingdesign will still be quite useful.

Therefore, because radiotelephones of existing construction may beutilized even subsequent to implementation of cellular systems ofincreased capacity, utilization of such radiotelephones of existingdesign will certainly continue. However, such continued use ofradiotelephone constructions of existing design would not permitadvantageous utilization of the additional transmission capacity of acellular, communication system of increased capacity. What is needed,therefore, is a system which permits a radiotelephone construction ofexisting design to utilize the features of a cellular, communicationsystem of increased capacity at minimal cost.

SUMMARY OF THE INVENTION

The present invention advantageously provides a system for upgrading aradiotelephone of existing construction.

The present invention further advantageously provides a mixed-modetransceiver system having at least two transceivers intercoupledtheretogether of which one of the transceivers may be comprised of aradiotelephone construction of conventional design, and a second of thetransceivers may be comprised of a radiotelephone construction of adesign capable of advantageously utilizing the additional transmissioncapacity of a cellular, communication system of increased capacity.

The present invention still further advantageously provides a method fortransmitting information signals in either of at least a firsttransmission mode, or a second transmission mode to a communicationnetwork.

In accordance with the present invention, therefore, a mixed-modetransceiver system operable on a communication network having at leastone fixed site capable of receiving and transmitting information signalsof at least first and second transmission modes is disclosed. Thetransceiver system is comprised of at least two transceivers wherein afirst transceiver of the at least two transceivers is operable totransmit information signals in the first transmission mode and a secondtransceiver of the at least two transceivers is operable to transmitinformation signals in the second transmission mode. At least one of thefirst and second transceivers contains a code which, when transmitted toa fixed site of the communication network, causes a communication linkto be created therewith. The first transceiver and the secondtransceiver are intercoupled to transfer the code provided to thecommunication network from the first transceiver to the secondtransceiver when the code is contained in the first transceiver totransmit the code in the second transmission mode. The code istransferred from the second transceiver to the first transceiver whenthe code is contained in the second transceiver to transmit the code inthe first transmission mode.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood when read in light ofthe accompanying drawings in which:

FIG. 1 is a partial block, partial schematic diagram of a cellular,communication system illustrating the positioning of a mobileradiotelephone and a portable radiotelephone proximate to a fixed sitecomprising a base station;

FIG. 2 is a block diagram of a radiotelephone of which either the mobileradiotelephone or the portable radiotelephone of FIG. 1 may becomprised;

FIG. 3 is a partial schematic, partial block diagram of tworadiotelephones intercoupled according to the teachings of the presentinvention;

FIG. 4 is a block diagram showing in greater detail the intercoupling ofthe radiotelephones of FIG. 3 according to the present invention;

FIG. 5 is a partial block, partial circuit diagram illustrating theintercoupling between the radiotelephones of FIG. 3 according to apreferred embodiment of the present invention; and

FIG. 6 is a flow diagram listing the method steps of the method of thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring first to the partial block, partial schematic illustration ofFIG. 1, the elements of a cellular communication system are shown. Asdescribed previously, the cellular, communication system is formed of aplurality of fixed-sites comprising base stations which are positionedat spaced-apart locations throughout a geographical area. The pluralityof base stations together comprise a portion of a fixed, communicationnetwork, referred to generally by reference numeral 100, comprisingelements at the left-hand side portion of the figure as defined by line106, shown in hatch. A plurality of fixed-sites forming base stations112 are positioned at spaced-apart locations throughout a geographicalarea. While two of such base stations 112 are illustrated in FIG. 1, itis to be understood that the system of the present invention isoperative to communicate with a single base station 112 formed of afixed-site, or, typically, a large number of base stations 112. Asindicated in the figure, each base station 112 comprises a transmitterportion 116, receiver portion 120, and antenna 124. Each base station112 is connected by a hard-line connection, indicated by lines 130, to aswitching center; such switching center is referred to in a cellular,communication system as a master cellular switch center (MCSC),indicated by the figure by block 136. MCSC 136 is, in turn, connected byhard-line connections, indicated by lines 142, to a conventionaltelephone network, as represented by central office block 148. Theconventional telephone network further comprises hard-line connections,such as indicated by line 154, to conventional, wireline telephones,such as telephone 160.

A radiotelephone, such as portable radiotelephone 166 or mobileradiotelephone 172 affixed within automobile 178 may transmit modulated,information signals to the receiver portions 120 of a base station 112when positioned proximate thereto, and may similarly receive modulated,information signals transmitted by a transmitter portion 116 of a basestation 112. A modulated, information signal transmitted by one of theradiotelephones, such as portable radiotelephone 166, once received by abase station 112 may be routed through the communication network 100 to,for example, wireline telephone 160, or another radiotelephone, such asmobile radiotelephone 172 affixed within automobile 178.

Turning now to the block diagram of FIG. 2, a transceiver (here, moreparticularly, a radiotelephone), referred to generally by referencenumeral 200, of which a radiotelephone, such as portable radiotelephone166 or mobile radiotelephone 172 of FIG. 1 may be comprised is shown.More particularly, transceiver 200 is of a construction permittingreception and transmission of signals upon either a cellular,communication system of conventional bandwidth or of reduced bandwidth,and is illustrated for purposes of example only. Such a transceiver isreferred to as being of a "dual-mode" construction. Other transceiverconstructions may, of course, be used in the system of the presentinvention. For instance, a transceiver construction operative to receiveand to generate discretely-encoded signals comprise many of the elementsof transceiver 200 of FIG. 2. Modulation and demodulation circuitrywould, however, differ corresponding to the modulation-type (i.e.,transmission mode) of the signal to be transmitted and received by thetransceiver. The actual circuitry embodying the functional blocks of thediagram may be disposed upon one or more circuit boards and housedwithin a conventional radiotelephone housing.

A signal transmitted by a base station, such as a base station 112 ofFIG. 1, and represented in FIG. 2 by transmitter 204, is received by aradiotelephone antenna 208. Antenna 208 supplies the received signal online 210 to filter 212. Filter 212 is preferably a very wideband filterhaving a passband to pass signal portions of a received signal within adesired frequency range. Filter 212 generates a filtered signal on line216 which is supplied to mixer 220. Mixer 220 additionally receives anoscillating signal on line 224 generated by oscillator 228. Oscillator228 preferably forms a portion of a conventional phase locked loop (notshown) having a frequency of oscillation controlled by a referenceoscillator (not shown) and a frequency divider, such as a programmablesynthesizer (also not shown). Mixer 220 generates a down-convertedsignal (commonly referred to as a first intermediate frequency, i.e.,IF, signal) on line 232. The down-converted signal generated on line 232is supplied to filter 236. Filter 236 is preferably a bandpass filter,such as a monolithic crystal wideband filter, and is commonly referredto as the first intermediate frequency, i.e., IF, filter.

Filter 236 generates a filtered signal on line 240 which is supplied toamplifier 244. Amplifier 244 generates an amplified signal on line 248which is supplied to second mixer 252. Line 256 is also coupled to mixer252 to supply an oscillating signal generated by oscillator 260 thereto.Similar to oscillator 228, the oscillation frequency of oscillator 260is locked into a known frequency relationship with a referenceoscillator (not shown).

Mixer 252 generates a mixed signal on line 264 which is supplied toswitching circuit 268. Switching circuit 268 may, for example, becomprised of an integrated circuit switch. Switching circuit 268alternately connects line 264 to lines 272 or 276. Line 272 is coupledto filter 280 of a first bandwidth, and line 276 is coupled to filter284 of a second bandwidth. The mixed signal generated by mixer 252 online 264 is filtered by either filter 280 or filter 284 responsive topositioning of the switch of switching circuit 268. When the switch ofswitching circuit 268 connects line 264 and 272, a filtered signal isgenerated by filter 280 on line 288. When the switch of switchingcircuit 268 is positioned to connect lines 264 and 276, filter 284generates a filtered signal on line 292.

Line 288 is coupled to amplifier/limiter 296 which generates anamplified signal on line 300 when a filtered signal is supplied toamplifier/limiter 296 on line 288. Similarly, line 292 is coupled toamplifier/limiter 304 which generates an amplified signal line 308 whena filtered signal is supplied to the amplifier/limiter 304 on line 292.Lines 300 and 308 are coupled to switching circuit 312 which, similar toswitching circuit 268 is preferably comprised of an integrated circuitswitch. Switching circuit 312 operates in the manner similar toswitching circuit 268 alternately to connect line 300 or 308 to line316. Line 316 is coupled to demodulator circuit 320 which demodulatesthe signal supplied thereto and generates a demodulated signal on line324 which is supplied to the transducer, such as speaker 330.

In a transceiver construction which is of a conventional design,switching circuits 268 and 312 are not required as line 264 is directlyconnected to filter 280 and amplifier/limiter 296 is directly connectedto demodulator circuit 320, and the parallel filter-amplifier/limiter284-304 line is not utilized.

The bottom portion of the block diagram of FIG. 2 further illustrates atransmit portion of the radiotelephone 200. As the transmit portion isconventional in nature (except for the modulator portion thereof whichis of a construction particular to the type of modulated, informationsignal to be transmitted by the radiotelephone, i.e., the desiredtransmission mode in which the radiotelephone is to be operated), adetailed description of operation thereof is omitted, but review of thefigure shows the transmit portion to include microphone 350 whichsupplies electrical signals to modulator 356. As mentioned hereinabove,modulator 356 is of a construction specific to the transmission mode inwhich the radiotelephone is to be operated. Oscillator 362 supplies anoscillating signal to modulator 356; a signal generated by modulator 356is supplied to mixer 368. Mixer 368 mixes the signal supplied thereto bymodulator 356 with an oscillating signal, and generates a mixed signalwhich is supplied, in turn, to filter 372, exciter 378, amplifier 382,directional coupler 386, and filter 392. Filters 392 and 212 maytogether form a duplexer.

Output power of a signal generated by radiotelephone 200 is controlledby power control unit 396 which is provided input signals generated byRF detector 400 on line 404. While not shown, control signals mayadditionally be applied to detector 400 and/or power control unit 396.

Turning now to the partial schematic, partial block diagram of FIG. 3,two radiotelephones are intercoupled theretogether to form aradiotelephone-pair, referred to by reference numeral 420. By suitablyintercoupling two radiotelephones theretogether, a data set forming acode (i.e., the access code mentioned hereinabove) contained in one ofthe radiotelephones which, when transmitted to a base station permitsformation of a communication link therebetween, may be transferred tothe other radiotelephone of the radiotelephone-pair 420. Therefore,radiotelephone-pair 420 is formed of first radiotelephone 426, here aportable radiotelephone similar to portable radiotelephone 166 of FIG.1, and second radiotelephone 432, here a mobile radiotelephone similarto mobile radiotelephone 172 of FIG. 1. Line 436, extending fromradiotelephone 426, and line 440, extending from radiotelephone 432, arecoupled theretogether by connectors 444.

FIG. 3 further illustrates peripheral devices coupled to radiotelephone432 such as handset 448, speaker 452, and microphone 456. Power supply460 is coupled to radiotelephone 432 to power the radiotelephonethereby. In a preferred embodiment of the present invention, whenradiotelephone 426 is intercoupled with radiotelephone 432 by connectors444, suitable connections are made between power supply 460 andradiotelephone 426 to permit radiotelephone 426 to be powered by batterysupply 460.

The data set forming the code contained in one of the radiotelephonesmay be contained in either first radiotelephone 426 or secondradiotelephone 432, or in both first radiotelephone 426 and secondradiotelephone 432. When the data set forming the code is contained inboth first radiotelephone 426 and second radiotelephone 432, theradiotelephones 426 and 432 may be separately operated with noconnection therebetween. Intercoupling of the first and secondradiotelephones 426 and 432 according to the present invention may bestill advantageously utilized even when data sets forming distinct codesare contained in both radiotelephones 426 and 432. For example, the dataset forming the code contained in one of the radiotelephones may betransferred to the other of the radiotelephones to form thecommunication link with the communication network for purposes ofbilling the resultant transmission to one or an other billing accountdefined according to the data set forming the code.

The data set forming the code, which, when transmitted permits formationof the communication link between the communication network and theradiotelephone, is preferably, as is conventional, comprised of numberassignment module (NAM) data. NAM data includes, for example, datasequences forming phone numbers, system identification numbers, systemchannel scan data, and radiotelephone serial numbers.

Intercoupling of two radiotelephones to permit transfer of the data settherebetween is particularly advantageous for the reason that aradiotelephone of conventional design may be intercoupled with aradiotelephone of a design permitting formation of modulated,information signals necessary for advantageous utilization of thefeatures of a cellular, communication system of increased capacity. Withreference to FIG. 3, for example, first radiotelephone 426 may becomprised of a portable radiotelephone of conventional construction, andthe data set may be contained within radiotelephone 426. Secondradiotelephone 432 may be comprised of a mobile radiotelephone of aconstruction permitting transmission of information signals capable ofsuch advantageous utilization of a cellular, communication system ofincreased capacity. When a user desires to transmit information in atransmission mode capable of utilizing the increased transmissioncapacity of a cellular, communication system of increased capacity, theportable radiotelephone is intercoupled, as shown, with mobileradiotelephone 432, the data set contained within radiotelephone 426 istransferred to mobile radiotelephone 432 from radiotelephone 426, andthe communication link with the communication network is formed bytransmission of the data set from radiotelephone 432 to a base stationof the communication network.

As previously mentioned, a cellular communication system may be utilizedat full capacity during only certain portions of the day, such as duringmorning and evening rush hour periods. The portable radiotelephone 426may be independently operated during most of the day, and intercoupledwith mobile radiotelephone 432 during those periods of the day in whichthe cellular communication system is fully utilized to make use of theadditional capacity of a cellular, communication system of suchincreased capacity. Because the data set forming the code is containedin the portable radiotelephone 426, the portable radiotelephone iscapable of independent operation during all hours. During rush hourperiods in which utilization of the additional transmission capacity ofa cellular, communication system may be necessary, the user mayintercouple the portable radiotelephone 426 with the mobileradiotelephone 432. The data set contained within radiotelephone 426 maybe transferred to mobile radiotelephone 432, and radiotelephone 432 maybe utilized to form the communication link with the communicationnetwork.

Turning now to the partial block, partial schematic illustration of FIG.4, the intercoupling between portions of first radiotelephone 426(indicated by the block shown in hatch at the right-hand side portion ofthe Figure) and second radiotelephone 432 (indicated by the block shownin hatch at the left-hand side portion of the Figure) ofradiotelephone-pair 420 of FIG. 3 is shown in greater detail. Connector444 couples data lines 436A, 436B, and 436C of radiotelephone 426 withcorresponding data lines 440A, 440B, and 440C of radiotelephone 432.Preferably, connector 444 forms a plug connector formed of mated pinconnectors disposed at ends of each of the data lines 436A-C and 440A-C.When suitably intercoupled theretogether, lines 436A-C and 440A-C form abus interconnecting processor 426A of first radiotelephone 426 andprocessor 432A of second radiotelephone 432. The bus formed therefrommay be operative to transfer data according to the protocol disclosed inU.S. Pat. Nos. 4,369,516 and 4,654,655. The resultant line formed oflines 436A-440A may thereby form a "true" (T) line; the resultant lineformed of lines 436B-440B may thereby form a "complement" (C) line; andthe resultant line formed of lines 436C-440C may thereby form a "return"line (R). Alternately a single line bus may be formed according to theprotocol disclosed in U.S. Pat. No. 4,972,432 to Gregory P. Wilson etal.; such single line bus is 20 referred to as a serial communicationsinterface (SCI) bus, in which the single line, such as the above-definedR line, is utilized to transmit data to radiotelephone 426 fromradiotelephone 432, and to transmit data to radiotelephone 432 fromradiotelephone 426.

Memory element 426B is coupled to processor 426A, and memory element432B is coupled to processor 432A. Memory elements 426B and 432B storealgorithms which are executable by processors 426A and 432A,respectively, and at least one of elements 426B and 432B stores the datasequence forming a code, such as the aforementioned-NAM information,which, when transmitted to a base station, permits a communication linkto be formed therewith. Further illustrated in the Figure are modulators426C and 432C which are coupled to processors 426A and 432A,respectively. Modulators 426C and 432C generate modulated, informationsignals by a desired modulation technique which are emitted by antennas426D and 432D over a desired transmission channel.

According to a preferred embodiment of the present invention,radiotelephone 426 comprises a portable radiotelephone of conventionalconstruction (i.e., the radiotelephone generates an analog, frequencymodulated signal of normal bandwidth according to a conventionalfrequency modulation technique, referred to hereinbelow simply by theterm "analog" technique) and radiotelephone 432 comprises a mobileradiotelephone capable of generating modulated, information signalscapable of utilizing the transmission capacity of a cellular,communication system of increased capacity. Accordingly, modulator 432Cgenerates a modulated signal according to a desired modulationtechnique, such as a discrete-modulation technique (e.g., a TimeDivision Multiple Access, TDMA, technique, or a Code Division MultipleAccess, CDMA, technique), or a reduced-bandwidth analog modulationtechnique (referred to hereinbelow as an "analog split channel"technique). As radiotelephone constructions capable of generating suchmodulated, information signals typically are further capable oftransmitting the analog, FM signals of conventional bandwidth (i.e.,"analog"), such radiotelephone constructions are usually referred to as"dual-mode" radiotelephones. Radiotelephones may also be constructed togenerate three different forms of modulated, information signals,referred to as "tri-mode" radiotelephones, as well as a plurality ofdifferent forms of modulated, information signals, referred to as"multi-mode" radiotelephones.

The following lists several of the many combinations of modulated,information signals which may be generated by adiotelephone circuitry ofvarious radiotelephone constructions: analog; analog split channel;digital TDMA; digital CDMA; analog/analog split channel; analog/digitalTDMA; analog/digital CDMA; analog/analog split channel/digital TDMA;analog/analog split channel/digital CDMA; analog/digital TDMA/digitalCDMA; analog split channel/digital TDMA; analog split channel/digitalCDMA; analog split channel/digital TDMA/digital CDMA; and digitalTDMA/digital CDMA. It is to be noted, of course, that suchradiotelephone construction-combinations may similarly be embodied by aportable radiotelephone, and that radiotelephone constructions may bedesigned to generate other modulated, information signals, and dual-,tri-, and multi-mode radiotelephones of other combinations may beconstructed. Therefore, while the above list is certainly notexhaustive, any of the above constructions may form radiotelephone 426and/or 432 according to the present invention.

Additionally, intercoupling of radiotelephones 426 and 432 permitscommunication between the respective ones of the radiotelephones, and,hence, radiotelephone 426 may utilize the circuitry of radiotelephone432 and vice versa. Preferably, communication between the tworadiotelephones 426 and 432 includes transfer of data includingsignalling transfer such as: intersignalling between the radiotelephonesto indicate times when the radiotelephones are intercoupledtheretogether, transfer of program information including data set aswell as repertory dial information, and other signalling transfer topermit one of the radiotelephones to utilize circuitry of the otherradiotelephone. For example, signalling transfer between portableradiotelephone 426 and mobile radiotelephone 432 may permit the portableradiotelephone to utilize circuitry of the mobile radiotelephone 432including mobile radiotelephone circuitry pertaining to transmitterpower, receiver sensitivity, antenna characteristics, as well as speakerphone functions, diversity, speech synthesis, and voice recognitioncapability.

Turning now to the partial block, partial circuit schematic of FIG. 5,the intercoupling between a radiotelephone pair such asradiotelephone-pair 420 of FIG. 3 according to a preferred embodiment ofthe present invention is shown in greater detail. Connector 490, shownin hatch in FIG. 5 corresponds to connector 444 of FIG. 3. Connector 490is a conventional plug-type connector which, in the preferredembodiment, comprises eight pin connections 494, 498, 502, 506, 510,514, 518, and 524. The right-hand side portion of the figure illustratesselected portions of the circuitry of a first radiotelephone, referredto by reference number 526, of the radiotelephone-pair, and theleft-hand side portion of the figure illustrates selected portions ofthe circuitry of a second radiotelephone, referred to generally byreference number 530, of the radiotelephone-pair.

In the following description, first radiotelephone 526 is a portableradiotelephone, and the second radiotelephone 530 is a mobileradiotelephone having circuitry permitting efficient transmission ofinformation upon a cellular, communication system of increased capacity.It is to be noted, of course, that other combinations of portable andmobile radiotelephone-pairs are possible, and that the circuitrypermitting most efficient transmission of information upon a cellular,communication system of increased capacity may, of course, be embodiedwithin radiotelephone 526 rather than radiotelephone 530. Additionally,according to the following description of the preferred embodiment, thedata sequence forming the code is contained within radiotelephone 526.The data sequence may, of course, be contained within adiotelephone 530rather than radiotelephone 526, or, alternately, different datasequences forming the code may be contained within both radiotelephones526 and 530.

Pin connection 494 indicates a speaker connection between theradiotelephone-pair 526-530. Pin connection 498 indicates a microphoneconnection between the radiotelephone-pair 526-530. Pin connection 502indicates a ground connection between the radiotelephone-pair 526-530.Pin connections 506, 510 and 514 indicate a 3-wire data bus connectionbetween radiotelephone-pair 526-530. Pin connection 518 indicates acommon-power connection between the radiotelephone-pair 526-530, hereindicated to be at a 9.5 volt potential difference above ground. Pinconnection 524 also indicates a ground connection betweenradiotelephone-pair 526-530.

Pin connections 494, 498, and 502 form audio connections betweenradiotelephone 526 and 530 which permit, for example, whenradiotelephone 526 comprises a portable radiotelephone, the portableradiotelephone to act as a handset of radiotelephone 530. Asillustrated, radiotelephone 526 includes speaker 534 and microphone 540which are connected to pin connections 494 and 498, respectively,through mute gates 544 and 548, respectively. Mute gates 544 and 548 areconnected by lines 552 and 556, respectively, to microcomputer 560.

When radiotelephone 526 is suitably intercoupled with radiotelephone530, speaker 534 and microphone 540 are connected to transceiver portion566 of radiotelephone 530. Transceiver portion 566 generates amodulated, information signal which is emitted by antenna 570 to bereceived by a base station such as one of the base stations 112 ofFIG. 1. Radiotelephone 526 of FIG. 5 further includes an on-off switch574 which may be actuated by a user alternately to power, or toterminate power, to radiotelephone 526 by radiotelephone 530. Whenradiotelephone 526 is not intercoupled with radiotelephone 530, switch574 is operative to power or to terminate the supply of power toradiotelephone 526 through an internal power supply 578 of theradiotelephone 526. Switch 574 may, for example, be comprised of amomentary switch operative to momentarily ground pin connection 498.Regulator 580 contained within radiotelephone 530 is enabled by switch574 to power radiotelephone 530, and, by way of pin connection 518, alsoradiotelephone 526. Other switches, although not shown, may also beincluded in circuitry to activate regulator 580. One such switchconfiguration is described in U.S. Pat. No. 4,798,975 issued on Jan. 17,1989, entitled "High Noise Immunity Input Level Detector withHysteresis", assigned to assignee of the present invention, incorporatedherein by reference.

Regulator 582 contained within radiotelephone 526 supplies theradiotelephone with power during intercoupling with radiotelephone 530.Pin connections 506, 510, and 514 permit transfer of data between theindividual ones of radiotelephone-pair 526-530. In a preferredembodiment, the data bus formed thereby may utilize data transfer schemesuch as those described in U.S. Pat. Nos. 4,369,516, and 4,654,655, thecontents of which are incorporated herein by reference. Briefly, pinconnection 506 interconnects the "T" lines of the three-wire bus, pinconnection 510 interconnects the "C" lines of the three-wire bus and pinconnection 514 interconnects the "R" line of the three-wire bus. The "T"and "C" lines are utilized to transmit data from microcomputer 584 ofradiotelephone 530 to microcomputer 560 of radiotelephone 526. The "R"line is used to transmit data from microcomputer 560 of radiotelephone526 to microcomputer 584 of radiotelephone of 530. Radiotelephone 526further includes microcomputer 588 which, as illustrated, is alsocoupled to the "T", "C" and "R" of the data bus. Microcomputer 588 ofradiotelephone 526 interfaces with keypad 592 and display element 596 ofthe radiotelephone. When suitably intercoupled, therefore, informationentered by a user upon keypad 592 may be transferred to microcomputer584 of radiotelephone 530 and to microcomputer 560 of radiotelephone526.

The algorithms executed by microcomputer 560 of radiotelephone 526 arestored in memory 600, such as a read-only memory. Similarly, thealgorithms executed by microcomputer 584 of radiotelephone 530 arestored in memories 604 and 608 which, as indicated, may be comprised ofread-only memory and random access memory, respectively. Microcomputer560 is additionally coupled to memory elements 612 and 616 which,preferably comprised EEPROM memories, and microcomputer 584 isadditionally coupled to memory elements 620 and 624, also formed ofEEPROM memories. In the preferred embodiment of the present invention,the data sequences forming the codes (which, when transmitted to a basestation form the communication link therewith) are stored in memoryelements 612, 616, 620 and/or 624. As noted previously, such dataincludes NAM information, and, also, repertory dialing information. TheNAM information, may for example, be contained in memory elements 612and 620, and the associated repertory dialing information may be storedin memory element 616 and 624. Microcomputers 560, 584, and 588 arepreferably comprised of Motorola Microprocessors, Model Nos. MC68HC11.

As noted hereinabove, radiotelephone 526 according to he preferredembodiment of the present invention comprises portable radiotelephone526, and radiotelephone 530 comprises a mobile radiotelephone.

Differences between the mobile and the portable are, at times,significant. One difference is that the mobile includes speciallydesignated RAM 608. The RAM 608 is used, in response to a request fromthe microcomputer 584 over the data transfer bus formed by pinconnections 506, 510 and 514 for storing the portable's NAM informationwhich is downloaded from EEPROM 612 of the portable. Such a datatransfer allows the mobile to assume the portable's identity forsubsequent communication on the system.

The mobile also accomodates downloading of the portable's repertorydialing information from EEPROM 616. This is accomplished by providingthat the mobile's EEPROM 624 is not only used for storing the mobile'srepertory dialing information, but also used, in response to a requestfrom the microcomputer 584 over the data transfer bus (506, 510, and514), for storing the portable's repertory dialing information which isdownloaded from EEPROM 616 of the portable. Preferably, the EEPROM 624is portioned into individual memory blocks, each of which is dedicatedto the particular radio's repertory information according to the radio'sassociated unique phone number.

An alternative method for the mobile to access the portable's repertorydialing information in EEPROM 616 is for the portable to transfer onlythe dialing information that is selected at the portable. This wouldminimize the amount of data to be transferred in situations where theuser only requires the mobile for limited usage. For example, consider asituation where the user desires to have the mobile assume theportable's identity for a single phone call. Once the intercoupling isestablished, the user selects a particular repertory dialing key on theportable (or corresponding key on the mobile). In response, the portabletransfers the necessary dialing information to the mobile fortransmission via the mobile's transceiver. When the call is complete,the user removes the portable for independent usage.

According to the present invention, by allowing the mobile to employ theportables' NAM and repertory dialing information, the user may employthe mobile as though it were the portable, thus, maintaining the sametelephone number and repertory dialing information while preventingsimultaneous radio usage of the same phone number.

Another difference between the portable and the mobile is that thetransceiver 630, conventional to any portable, may be disabled inresponse to the microcomputer 560 detecting the availability andselection of the more powerful mobile transceiver 566. The detection isaccomplished by the microcomputer 560 monitoring the 9.5 V connection518 through a line conditioner circuit 634. The line conditioner 634 maybe implemented using a bipolar transistor. Its function is to convertthe 9.5 V signal to a binary signal to indicate whether or not the 9.5 Vsignal is present. The selection of the mobile transceiver 566automatically occurs after the portable is intercoupled with the mobileand communication is established between the two radios. The selectionto employ the mobile transceiver may also be manually implemented byproviding for an user code, e.g. key sequence, which is programmed intothe portable's keypad 592 to instruct the mobile to enable itstransceiver accordingly.

A third difference involves the portable power supply. As previouslydiscussed, the switch 574 on the portable actuates a voltage regulator580 in the mobile to provide power to the portable during theintercoupling mode. Commensurate with this intercoupling, the powerwhich is internal to the portable, battery 578 is disabled. This isaccomplished through the use of a protrusion 638 on the connector. Whenthe intercoupling is made, the protrusion 638 opens a switch 642 whichdisables internal power from being provided to the portable. While theportable is not intercoupled with the mobile, the switch 642 is normallyclosed. A diode 646 is connected between the battery 578 and theconditioner 634 to prevent the battery 578 from falsely indicating thepresence of the 9.5 V from the mobile.

As previously discussed, one advantage of the radio intercoupling isthat the portable is able to employ a number of mobile features whichwould not otherwise be available. The manner in which the portableemploys the mobile's transceiver circuitry has been discussed above. Adescription of the manner in which the mobile's voice-speaker phone andvoice recognition and speech synthesis circuitry follows.

The mobile's voice recognition and speech synthesis circuitryvoice-speaker phone is depicted by block 650 of FIG. 5. After the radiointercoupling is established, the user enables the mobile's V/SP 650 byeither entering a special key code into the portable's keypad 592 or byspeaking a special command into the microphone 654.

Once the mobile's V/SP 650 is enabled, the user employs the speaker 658and the microphone 654 as normal. The V/SP 650 decodes the speaker'sverbal commands and provides the decoded information to themicrocomputer 584, which information initiates data transfers to thetransceiver 566 and to the portable's display 596.

The V/SP 650 may be implemented by using a conventional voicerecognition/speech synthesis system. Although the V/SP 650 is showncommunicating with the microcomputer via an independent connection, thedata transfer bus (506, 510, and 514) may alternatively be employed.

The mobile's voice-speaker phone operation is utilized by entering aspecial key code into the portable's keypad 592. When the special keycode is recognized by the microcomputer 584, the microcomputer 584instructs the V/SP to enable the speaker 658 and the microphone 654 forthe user's use. The speaker 658 and the microphone 654 are disabledeither by a second special key code, by disconnecting the portable fromthe mobile or by lifting a separate handset 448 (connected to the mobileas shown in FIG. 3) off hook.

Turning now to the flow diagram of FIG. 6, the method steps of themethod of the present invention are illustrated. First, and as indicatedby block 700, at least two transceivers are intercoupled theretogetherwherein at least one of the transceivers contain a code which, whentransmitted to a fixed site of a communication network, permits acommunication link to be created therewith. Next, and as indicated byblock 704, the code is transferred to the first transceiver when thecode is contained in the second receiver and an information signal is tobe transmitted in the first transmission mode. Next, and as indicated byblock 708, the code is transferred to the second transceiver when thecode is contained in the first transceiver and an information signal isto be transmitted in a second transmission mode. Next, and as indicatedby block 712, the code is transmitted to a fixed site of thecommunication network to permit formation thereby of a communicationlink between one of the at least two transceivers and the communicationnetwork.

In a preferred embodiment of the present invention, and as indicated byblock 716, upon disconnecting the interconnected radiotelephones, thetransferred code is erased in the accepter radio to prevent two radiosfrom having the same code set on the system at the same time.

When, according to a preferred embodiment of the present inventionillustrated in FIG. 5, radiotelephone 526 is comprised of a portableradiotelephone of conventional construction, and radiotelephone 530 iscomprised of a mobile radiotelephone having circuitry to permitefficient transmission of information upon a cellular, communicationsystem of increased capacity, intercoupling of the radiotelephones 526and 530 theretogether permits transfer of the NAM information containedin memory elements 612 of radiotelephone 526 to microcomputer 584 ofradiotelephone 530. Once transferred to microcomputer 584, such NAMinformation may be supplied to transceiver portion 566 whereat the NAMinformation is modulated according to a desired technique and suppliedto antenna 570 to be transmitted therefrom. Because the NAM informationneed only be stored in radiotelephone 526, separate access fees requiredto provide unique NAM information to each of the radiotelephones 526 and530 is not required. Utilization of the more efficient transmission ofinformation according to a cellular, communication system is permittedof portable radiotelephone 526 when suitably intercoupled with mobileradiotelephone 530. Conversely, when radiotelephone 526 is notintercoupled with radiotelephone 530, radiotelephone 526 is alsopermitted to be operated to form a communication link with a cellular,communication system to transmit information signals therebetween.

While the present invention has been described in connection with thepreferred embodiments shown in the various figures, it is to beunderstood that other similar embodiments may be used and modificationsand additions may be made to the described embodiments for performingthe same function of the present invention without deviating herefrom.Therefore, the present invention should not be limited to any singleembodiment, but rather construed in breadth and scope in accordance withthe recitation of the appended claims.

What is claimed is:
 1. A method of controlling a cellular radiotelephoneincluding a controller, transceiver circuitry coupled to the controllerto communicate with a fixed radio site, and a receptive coupler coupledto the controller to receive an external intercoupler, comprising thesteps of:communicating through the receptive coupler with amicroprocessor associated with the external intercoupler to obtain acode of a data set; establishing via the transceiver a communicationlink with the fixed radio site using the code while said receptivecoupler receives said external intercoupler; and precluding, by thecontroller, the establishment of a subscriber communication link withthe fixed site using the code upon disconnection of the externalintercoupler from the receptive coupler.
 2. The method as defined inclaim 1, wherein said step of communicating with the external devicemicroprocessor includes communicating between the radiotelephoneprocessor and the external device microprocessor to receive the codefrom the external device microprocessor.
 3. A radiotelephone forcommunicating in a cellular radio system having at least one fixed radiosite and a plurality of radio telephone units, the radiotelephonecomprising:a radio transceiver; and a receptive coupler coupled to theradio transceiver for receiving an external intercoupler, said receptivecoupler being adapted to communicate with a microprocessor associatedwith the external intercoupler to receive a code related to a data setand establishing a communication link with the fixed radio site via theradio transceiver using the code only while said receptive couplerreceives said external intercoupler.
 4. A radiotelephone according toclaims 3, wherein the receptive coupler is adapted to receive a coderelated to user identification information uniquely associated with auser.
 5. A radiotelephone according to claim 3, wherein the receptivecoupler is adapted to receive a code related to a telephone numberuniquely associated with the user.
 6. A radiotelephone according toclaim 3, wherein the receptive coupler is adapted to receive a coderelated to one of transmitting power, receiving sensitivity, repertorydialing numbers, or telephone functions.
 7. A cellular radiotelephonesystem, comprising:a portable device including a microprocessor toselectively access an identification code stored in the portable deviceand an external connector coupled to said microprocessor; and aradiotelephone for communicating with at least one fixed radio site,said radio telephone comprising:radio transceiver circuitry; a radioconnector to releasably receive said external connector; and circuitryconnected between said radio connector and said radio transceivercircuitry, said circuitry communicating said identification code betweensaid microprocessor and said transceiver circuitry to effect aconnection between said microprocessor and said radio transceivercircuitry, said radio transceiver circuitry selectively establishing acommunication link with the fixed radio site using said identificationcode only while said radio connector receives said external connector,wherein the radiotelephone's identification is taken from said portabledevice only while said portable device and said radiotelephone areinterconnected.
 8. The cellular radiotelephone system as defined inclaim 7, wherein said circuitry includes a processor controllingoperation of the radio transceiver circuitry and communicating with theexternal microprocessor through the connector.